This one will sneak up on you if you drop your guard. It's "The Tic Code," a drama about a 12-year-old with Tourette's syndrome. If it seems to have the ingredients of an after-school special, the performances take it to another level.

Gut level.

Tourette's is probably most commonly known as the thing that causes people to burst out with streams of obscenities. Miles, the afflicted youngster in "The Tic Code," is more likely to blink, twist his neck, hesitate or make little clicking vocalizations before speaking. Then he has a tendency to say whatever is on his mind.

Miles is played by Christopher Marquette. The kid is remarkable, but the really moving performance is by Gregory Hines, as a jazz saxophonist who understands the boy's code of tics and compulsions.

Hines, one of America's great dancers, slips effortlessly into the skin of Greenwich Village jazzman Tyrone Pike. Hines has got the moves, the delivery, the attitude, and when it comes to playing the sax, many viewers are going to want to stick around for the credits just to find out if he's really doing it himself.

Someone with Tourette's can escape the symptoms when totally absorbed in something else. In Miles' case, it's when he's playing the piano, flat-fingered (instead of cupped) like his hero, Thelonious Monk. The improvisatory, absorbing world of jazz is a good fit for people with Tourette's.

Miles must surely be named for the jazz trumpeter Miles Davis. His jazz-loving single mom, Laura, is played by Polly Draper ("thirtysomething"), who also wrote the script. Draper's husband has Tourette's.

Miles is a handful. His tendency to blurt out whatever crosses his mind can annoy even those closest to him. "I'm not holding by breath," he says. "I'm holding my feelings." He reassures himself by the compulsive touching of certain objects and other repetitive patterns. From time to time, "The Tic Code" goes into black and white when Miles is in the grip of Tourette's.

The boy's father occasionally drops out of the sky for quick visits at the airport, but generally Miles seems to be an embarrassment to him.

The same medical skin patches that might relieve his symptoms also flatten out his responsiveness to life. Laura, a seamstress, pretty much has dropped out of life to take care of him.

"Seamstress" -- if that word sounds as if it comes from a Victorian melodrama, just relax and go with it here. The heartfelt emotions this movie brings out benefit from exercise.

Attracted first by Tyrone's obvious sympathy with her son and smoothness in dealing with him, Laura finds herself falling for the man. Draper and Hines have a very sexy scene when Laura fits Tyrone for a jacket.

Tyrone, however, keeps Laura at arm's length -- she persists in bringing up the one subject he doesn't want to talk about.

Actually, Laura was attracted first by his playing -- she was a fan of his before she met him. In Hines' performance, it's completely understandable. "The Tic Code" may have a couple of awkward sequences, but the jazz milieu keeps it centered.